Lower Digestive System Flashcards
(23 cards)
What are the 3 sections of the small intestine?
- Duodenum
- Jejunum
- Ileum
What is the duodenum and what does it do?
Short tube which exits the stomach on the right side of abdomen and receives ducts from the pancreas and liver
What is the jejunum and what does it do?
Longest tube, which digests and absorbs nutrients
What is the ileum and what does it do?
Shortest tube lined with lymphocytes for gut immunity which joins the large intestine at the ileoceceal junction
What is emulsification?
Physical breakdown of fats into small droplets
What is the digestive function of the liver?
- Hepatocytes produce bile which contains bile acids, which emulsify big droplets of fats into small droplets
- Bile is stored in the gall bladder
- Converts fatty acids into phospholipids and cholesterol
- Stores glucose as glycogen
- Use digested amino acids to make new protein or covert it to glucose
- Converts wasted ammonia to urea
- Detoxification
- Stores iron and vitamins
- Excretes bilirubin (breakdown product of haemoglobin)
What is the digestive function of the pancreas?
Secrete digestive enzymes and sodium bicarbonate which neutralises stomach acid
What are the 3 main digestive enzymes?
- Trypsin and peptidases
- Amylase
- Lipase
How are proteins digested?
Typsin digest proteins into peptides and eventually amino acids by peptidases
How are carbohydrates digested?
Amylase digest starch into disaccharides and then monosaccharides by lactase or sucrase
How are fats/lipids digested?
Fats are emulsified by bile and then lipase digests the fats into fatty acids and glycerol
Describe small intestine motility
Segmentation alternates contraction and relaxation to mix chyme and digestive enzymes
- Peristalsis for one-way progression of chyme along the small intestine
How are nutrients absorbed in the small intestine?
- Amino acids and sugars absorbed into blood capillaries and carried by hepatic portal vein to liver for further processing
- Fatty acids absorbed into lymphatics
What are the 3 sections of the large intestine?
- Caecum
- Colon
- Rectum
What is the function of the caecum and colon?
- Absorbs water and electrolytes forming chyme into solid faeces
- Have goblet cells to secrete mucous with lubricates faeces
- Large numbers of bacteria to prevent pathogens colonising
- Storage of faecal matter in colon
What does diarrhoea in the small intestine look like?
- Large volumes and very watery liquid
What does diarrhoea in the large intestine?
- Small volumes
- Increased frequency
- Variable consistency often containing blood and mucus
How do herbivores digest cellulose?
Ferments cellulose in the gut and produces volatile fatty acids, which as used as energy
What are foregut fermenters called?
Ruminants
What is a diastema and where is it found?
A gap between incisors and cheek teeth in ruminants
How many chambers does the ruminant stomach have?
4
Why is muscular contractions for forestomach motility beneficial?
- Mix contents of the rumen promoting fermentation
- Allows cud to be regurgitated to be re-chewed and re-swallowed
- Allows eructation (Built up CO2 or methane gas is expelled)
What causes bloating in the ruminant and why is it dangerous?
Oesophagus is blocked or ruminant is stuck upside down, which means tehy cannot burp the gas out and therefore will die
